Tivoli Storage Manager for Windows Administrator's Guide


Overview of Setting Up a Tape Rotation

Tape rotation, as it applies to TSM, refers to the ongoing circulation of tapes through the storage management process. Once TSM selects an available tape, the tape is used and eventually reclaimed according to its associated policy. TSM tape rotation does not generally consist of an administrator backing up a given data set to tape and then repeatedly overwriting that tape with the same data set.

TSM manages the data on tape and optical disk media, but administrators manage the physical media. Administrators can manage media themselves, with some help from TSM, or they can extend media management capabilities by using a removable media manager. Regardless of the methods or tools used, managing media typically leads to setting up a media rotation. A media rotation is a media management scheme that captures the data retention and media reuse goals of the administrator. It requires that administrators create policy to expire aged (and now invalid) data, reclaim valid data onto new media, and reuse the physical media.

As part of managing the data on volumes, administrators tune expiration processing and data reclamation.

TSM places information into the volume history log about tapes used for database backups and exports (for disaster recovery purposes). The process for reusing these tapes is slightly different than the process for reusing tapes containing client data backups.

The data on a tape or optical disk volume changes over time as a result of:

Figure 8 illustrates a typical life cycle for scratch tapes. The use of scratch tapes is recommended. The private or scratch status of tapes is determined when devices are configured; specifically, when storage pools are created for the device media. When working with new media this is important because even before TSM knows about tapes, an implication exists that tapes have a status of either scratch or private as a result of the storage pool defined for the media when the device was configured for TSM.

Figure 8. Simplified View of Tape Rotation

Simplified View of Tape Rotation

Numbers in the following text (such as (1)) refer to numbers in Figure 8.

(1) Label tapes.
See Labeling Media for use with an Automated Library Device or Labeling Media for use in a Manual Library Device.

(2) Determine whether tapes are scratch tapes or private tapes.
This decision is made when devices are configured for TSM. See Overview of Volumes.

(3) Check the tapes into their respective libraries.
Checking tapes into manual library devices is a matter of storing the tapes, for example, in a file cabinet or desk drawer. Checking tapes into automated library devices requires the administrator to add new tapes to the volume inventory. See Checking Media into Automated Library Devices.

(4) Set up expiration processing.
Expiration processing is a step in the data deletion process where the server removes database entries, effectively deleting data. Administrators control expiration processing through TSM policy. After tapes have been labeled and libraries are populated, administrators set up expiration processing by either accepting the TSM data expiration defaults or by modifying TSM policy for the desired data expiration. See Basic Policy Planning.

(5) Set up reclamation processing.
As data expires, much of the data on tapes becomes invalid. Administrators can set up reclamation processing to reclaim valid TSM data and reclaim physical media. See Reusing Media - Reclamation Processing.

(6) Ongoing TSM tape processing.
See TSM Volume Processing.

(7) Determine when tapes have reached their end of life.
See Determining When Media has Reached Its End of Life.


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